C6 Corvette Z06 Suspension - Suspension A La Carte

Redline Motorsports And Pfadt Race Engineering Put A C6 On The Fast Track To Road-Course Prowess

The results were immediately noticed on the way back to the track. "Just when you think you're about to start driving a street-legal race car, you start to appreciate what the coilovers and sway bars have done to the car's feel. I always felt the Z06 handled incredibly, but now I realize how much room there was for improvement," opined Tanner.

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Adding stiffer sway bars and springs typically has a negative effect on a car's ride characteristics, but that wasn't the case in this instance. Tanner told us that the improved damping and spring rates of the adjustable Pfadt coilovers helped the car stay comfortable without blunting its aggressiveness in turns-and the Porsche-killer setting is only an adjustment away.

There are 16 adjustment clicks built into the Pfadt coilovers; the company recommends starting by turning the knob counter clockwise until it stops, which is full soft. Adjustments are made from there and described by click count for consistent adjustments. For the street, Tanner set his at six clicks from full soft in the front and back.

"The 'six and six' adjustment will give a comfortable ride and increased performance. A lot of people use those settings for mostly street-driven cars and very limited track time, like Howard's car," said Aaron Pfadt, owner of the company that bears his name. We queried the suspension guru on what settings are needed to step things up a notch. "For the track, I recommend 10 clicks from soft in the front and 12 in the rear. That is a great starting point, and you can fine-tailor it from there," Pfadt said. "It stiffens up the dampening, and that is what plays a big role in stiffening the car. It won't be a harsh ride like a race car, but it does firm it up. Most people use that setting on the track, but we do have customers who run those settings on the street and don't mind it." The sway bars were set up to Pfadt's recommended settings, which are explained clearly in a comprehensive instruction manual.

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On track, Tanner's initial assessment of better handling was confirmed as the twin-turbo Vette ran a new best two-lap run of 45.20 seconds (a 1.1-second gain) using the street-friendly six-click settings. We checked back with Tanner a few weeks after the on-track testing to see if he was still giddy about the new mods.

"The true test came when I really started pushing the car through the highway on-ramps in the past few weeks. I didn't feel any body roll, and the car felt predictable as I pushed it deep into the turns. Normally, hitting bumps in a turn with a Corvette can be a bit unnerving. The Pfadt true independent suspension, however, allows the car to hit the bump, and the three other wheels stay planted. The suspension mods not only increase the limits of the vehicle but also add control to make it easier to drive. It's very reassuring as a Vette owner."

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Special thanks to Albany-Saratoga Speedway for opening up its track for our testing. Check the track's website (www.CVRA.com) for more info on its street nights.

The first step for Redline's Howard Tanner was to measure the ride height at all four corners. The front checked in at 23 13/16 inches on the right and 23 11/16 inches on the left. (The difference was traced to a bad bushing.) The rear heights were 24 7/8 inches on the right and 24 9/16 inches on the left.

The front sway bar was easily unbolted and removed.

The difference is obvious between the stock (bottom) and the Pfadt sway bar. The front OEM piece comes in at 1.2 inches thick, while the Pfadt shows up to the party at 1.5.

The Pfadt bar offers a significant amount of adjustment, with firm and solid mounting. The stocker uses flimsy rubber bushings, a choice dictated by manufacturing cost and ride-comfort concerns.

Pfadt sway bars are adjustable and use splined ends to hold the arms in place. They were adjusted per the instructions.

The front shocks are removed to make way for the Pfadt coilovers.

Like the sway bars, the difference between the stock shock (top) and the Pfadt coilover is obvious. The Pfadt pieces offer adjustable dampening and adjustable springs for ride height.

Here's the adjuster knob to control the dampening of the shock. Tanner has it set to six clicks from soft (front and back) for street use. Track recommendations are 10 clicks from soft up front and 12 clicks in the back.

The bottom of the coilover shock acts as the mount; it's very durable thanks to its billet-aluminum construction.

Ride height is controlled by the spring adjustments, which are handled by two adjuster rings. One is to set the height, and the other is to lock it in place.

It might be old technology, but the monospring is still an effective component. The Pfadt coilovers allowed us to remove the monosprings, making the suspension a true independent setup.

The shock-mount bolt holes on the Z06's control arms had to be enlarged to accept the Pfadt coilovers.

The shocks bolted in easily...

...once the bolt hole was enlarged.

Once the front end was modified, Tanner moved to the rear of the vehicle.

The OEM mounting bracket was reused but required a few washers to account for the extra thickness of the Pfadt sway bar.

With the stock shocks removed...

...the Pfadt units slid in easily.

A comparison of the rear sway bars shows the stock bar has a 1.11-inch diameter, while the Pfadt checks in at 1.25.

The OEM mounting bracket was reused but required a few washers to account for the extra thickness of the Pfadt sway bar.

After dropping the car and driving it around the block (to allow the suspension to settle), Tanner set up the front corners at 24.5 inches and the rears at 25.

The front end was raised a little for extra ride height, since the APS twin-turbo system has two pipes running underneath the front suspension. "In the end, if the car sits a tad higher but rides and handles better, I don't mind one bit," said Tanner

On track, the car cut its previous two-lap time of 46.30 seconds down to 45.20. Street feel was greatly improved as well, with a slightly stiffer feel but much better performance.

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